1. Technical Field
The present invention relates to a sensor unit, an electronic apparatus using the sensor unit and a moving object.
2. Related Art
A physical quantity sensor such as an acceleration sensor or an angular velocity sensor is widely known. The physical quantity sensor is mounted on a mount board by connecting a mount terminal provided on the mount board and a terminal provided on the physical quantity sensor. As the mount terminal, for example, a land grid array can be used. The land grid array includes plural mount terminals arranged in a line along the contour of the physical quantity sensor. The plural mount terminals can be arranged in a line along, for example, one side of the square contour, or form a line so as to go round the contour. In recent years, with miniaturization of an electronic apparatus using a sensor unit, miniaturization of the sensor unit is required, and the mounting density thereof increases. Thus, wirings connected to the mount terminals become complicated, and the wirings are generally provided also on an inner periphery where the mount terminals are arranged.
JP A-2007-195145 is an example of related art.
However, the foregoing physical quantity sensor has a temperature characteristic. An output signal at the time of no load (physical quantity to be detected does not act), that is, a zero point voltage is changed according to temperature change. The change occurs according to the temperature change. According to the observation of the inventor, it was found that when a wiring made of a conductive material was provided in a region overlapping a physical quantity sensor mounted on a mount board when viewed in plan, a singular point (hereinafter referred to as “bias shift”) occurred in a specific temperature region in the hysteresis of the temperature characteristic of the physical quantity sensor. There is a problem that when the bias shift occurs, the zero point voltage significantly varies in the specific temperature region, and excellent temperature characteristics can not be obtained. Besides, there is a fear that the reliability of measurement results is lowered by the bias shift.